Functional characterization of RelBE toxin-antitoxin system in probiotic Bifidobacterium longum JDM301
Functional characterization of RelBE toxin-antitoxin system in probiotic Bifidobacterium longum JDM301
复制标题
益生菌长双歧杆菌 JDM301 中 RelBE 毒素-抗毒素系统的功能表征
DOI：
10.1093/abbs/gmw056
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发表时间：
2016
影响因子：
3.7
通讯作者：
Liu Chang
中科院分区：
文献类型：
--
作者：
Wei Yanxia;Ye Lu;Li Yang;Yang Fan;Liu Dianbin;Guo Xiaokui;Tang Renxian;Liu Chang
毒素-抗毒素(TA)系统广泛存在于细菌和古生菌中。然而，染色体编码的TA系统在细菌生理学中的作用仍然存在争议。在本研究中，我们鉴定了一个新的TA编码模块--relBEinBEinBifidbacterium long umJDM301(RelBEBif)，并对其在胁迫反应中的功能进行了评价。对JDM301全基因组序列的生物信息学分析显示，有一对连锁基因编码一个类似RelBE的TA系统(RelBEBif)。我们的结果揭示了由relBEBifin JDM301形成的双顺反子操纵子。过表达的RelEBif对大肠杆菌有毒害作用，其同源抗毒素RelBBif的共表达可中和这一作用。我们的数据还表明，RelEBifi是一种mRNA干扰酶，RelEBifi的活性可以被RelBBif抑制。这些结果表明，RelEBif是一种通过mRNA降解抑制细胞生长的有毒核酸酶，RelEBif的活性可以通过与RelBBif的共表达而被取消。此外，我们还发现，在渗透胁迫过程中，RelBEBifis的表达增加，这表明在这种不利的条件下，RelBEBifis被激活。我们的结果表明，RelBEBifTA模块可能代表了一种帮助B的细胞生长调节剂。龙来应对渗透压力。
Toxin–antitoxin (TA) systems are widespread in bacteria and archaea. However, the roles of chromosomally encoded TA systems in bacterial physiology are still open to debate. In this study, a TA module–relBEinBifidobacterium longumJDM301 (relBEBif) was identified and its function in stress response was evaluated. Bioinformatics analysis of the whole genome sequences of JDM301 revealed a pair of linked genes encoding a RelBE-like TA system (RelBEBif). Our results revealed a bicistronic operon formed byrelBEBifin JDM301. Over-expression of RelEBifhad a toxic effect onEscherichia coli, which could be neutralized by co-expression of its cognate antitoxin, RelBBif. Our data also demonstrated that RelEBifis an mRNA interferase and that the activity of RelEBifcan be inhibited by RelBBif. These results suggest that RelEBifis a toxic nuclease which arrests cell growth through mRNA degradation, and that the activity of RelEBifcan be abolished by co-expression of RelBBif. In addition, we also found that the expression of RelBEBifis increased during osmotic stress, suggesting that RelBEBifis activated under this adverse condition. Our results imply that the RelBEBifTA module may represent a cell growth modulator which helpsB. longumto deal with osmotic stress.